(a) Field of the invention.
This invention relates to improvements in couplings. More particularly, the invention concerns frictioncouplings adapted to resist and so far as possible to prevent relative rotational movement between a rotatable male member, such for instance as a shaft, and a bore in a female member within which it is axially movably located, such for instance as a bore in a hoursing, a cylinder, a bearing, an annulus or indeed other member capable of receiving such a male member.
(B) Description of the prior art.
Hitherto, friction-locking or friction-coupling devices have mostly been associated with the threaded portion of male and female members joined together by screw-threading, because of the difficulty in producing an effective friction-coupling between such members at non-threaded positions. Such an arrangement however not only restricts the location of the coupling device and introduces problems such as burring of the threads, but also the friction-coupling then must be precisely machined to fine tolerances so as to enable it to be properly located, and yet even then problems can still arise in locating the coupling. A friction-locking device has however been proposed in British Patent No. 1,393,257 which takes the form of an imperfect circle or ring, which is adapted to be interposed between rotatable members being coupled, and which holds or couples these members together frictionally through imperfections in the circle that provide points of frictional contact therewith.